How does the character of the Sastry transition depend on the range of interatomic interactions?

The mean pressure <P_IS(ρ)> within the inherent structures (IS) of liquids maintained at density ρ and temperature T >> Τ_melt is minimized at the “Sastry” density ρ_S. For ρ < ρ_S (ρ > ρ_S), these IS are typically cavitated (homogenous). Using molecular dynamics simulations of Mie liquids [U_n(r) = ε(r^-2n - 2r^-n) with 4 ≤ n ≤ 12], we determine how the character of the transition between cavitated and homogeneous IS depends on the range of the interatomic pair potential. We find three principal results: (i) As n increases with T held fixed, ρ_S approaches and then exceeds the crystallization density ρ_X; (ii) as a consequence, the portion of systems’ phase diagrams (in terms of P and T) where systems are liquids with predominantly cavitated IS decreases with increasing n; (iii) For ρ > ρ_S, the pair correlation functions g(r) of the liquids’ IS are nearly conformal, i.e. the g(r) for different n nearly map to a common reduced pair correlation function G(ρ^1/3r) = ρ^-1/3g(r). We discuss the implications of these results for condensation and cavitation of simple atomic liquids.